Sample_Exam_1_09s

# Sample_Exam_1_09s - Sample Exam 1 - Physics 130 Short...

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Sample Exam 1 - Physics 130 Short Answer Section 1 . Estimate the volume of gold in a solid gold wedding ring. The density of gold is 19.3 × 10 3 kg / m 3 . r inner = 1 cm = 1 × 10 2 m r outer = 1.2 cm = 1.2 × 10 2 m h = 0.4 cm = 4.0 × 10 3 m volume = π ( r outer 2 r inner 2 ) h = 0.55 cm 3 2. Your Fngernails grow approximately 6 inches per year. What is the speed in m/s? s = yr 6 in \$ 1 in 2.54 cm \$ 100 cm 1 m \$ 365 days 1 yr \$ 24 h 1 day \$ 3600 s 1 h = 4.83 # 10 -9 m / s 3. You attend a rock concert on the grounds of a football Feld that is packed with people. If the Feld is 150m long and 100m wide, estimate the size of the crowd at the concert. Take the space that each person has to be a circle of radius 1m. Is your estimate too low or too high? A total = # people A person # people = A A = 150 m 100 m (1 m ) 2 = 4774 This estimate is probably too low if the Feld is really packed. People will be closer than 2m. 4. Boulders on movie sets are often made of light materials like Styrofoam. If we approximate the shape of a boulder as a cylinder of radius 1.0 m, and length 3m, what is the mass of this false boulder. The density of Styrofoam is 0.92 kg/m^3 m = ρ V = 0.92 kg m 3 m ) 2 3 m = 8.67 kg 5. When the space shuttle re-enters the earth's atmosphere, it is traveling at 25 times the speed of sound. If the speed of sound is 340 m/s, calculate the shuttle's speed in m/s, and mi/hr. s = 25 340 m s = 8.50 × 10 3 m s = 8.50 × 10 3 m s 1 mi 1600 m 3600 s 1 hr = 19,125 mi hr

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6. A hailstone forms in the clouds of a thunderstorm approximately 1000ft above the earth's surface and falls to the ground. What velocity does it have when it hits the earth. If this is so, why aren't hailstones lethal? a = g = 32 ft / s 2 y f = 1000 v i = 0 / s v f 2 = v i 2 + 2 a ( y f y i ) v f 2 = 2 32 s 2 1000 v f = 253 s 60 mi/hr=88 ft/s. Hailstones don’t go this fast because of friction. 7. How long did it take the hailstone to reach the earth in the previous question?
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## This note was uploaded on 09/27/2010 for the course ASD 2456 taught by Professor Jojo during the Spring '10 term at Brooklyn Law School.

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Sample_Exam_1_09s - Sample Exam 1 - Physics 130 Short...

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